Why there is different codes to print hello world in different pc apps ? Which app is the best ?

Answer 1

What do you mean by apps? You probably mean LANGUAGES ?

Answer 2

ok but why

Answer 3

obviously, Because EACH language has it's own Set of Instructions. We call this instruction code as SYNTAX, which is MANIPULATED or UNDERSTOOD by the compiler of THAT language.
You can understand it in the following way:
In Real Life:
Hello in English-Hello
In Spanish-Hola
In French-Bonjour
In Hindi-Namaste

Similarly, in COMPUTER LANGUAGES:
In BASIC: PRINT "HELLO WORLD"
In C: printf("Hello World");
In JavaScript: document.write("Hello World");
In PHP: echo "Hello World"

Answer 4

but in c++ and in different software of c++ it is different

Answer 5

that because of difference on compiler version